Kendrickichthys is a basal member of the clade Aspinothoracidi, which belongs to the clade Pachyosteomorphi, one of the two major clades within Eubrachythoraci. The cladogram below shows the phylogeny of Kendrickichthys:2
Coccosteomorphi
Rhachiosteus pterygiatus
Eastmanosteus calliaspis
Eastmanosteus pustulosus
Kiangyousteus yohii
Golshanichthys asiatica
Westralichthys uwagedensis
Dunkleosteus raveri
Dunkleosteus terrelli
Dunkleosteus amblyodoratus
Heterosteus ingens
Yinosteus major
Tapinosteus heintzi
Bullerichthys fascidens
Kendrickichthys cavernosus
Bruntonichthys multidens
Dinichthys herzeri
Hadrosteus rapax
Gorgonichthys clarki
Heintzichthys gouldii
Pachyosteus bulla
Gymnotrachelus hydei
Stenosteus angustopectus
Brachyosteus dietrichi
Melanosteus occitanus
Rhinosteus parvulus
Zhu, You-An; Zhu, Min; Wang, Jun-Qing (1 April 2016). "Redescription of Yinostius major (Arthrodira: Heterostiidae) from the Lower Devonian of China, and the interrelationships of Brachythoraci". Zoological Journal of the Linnean Society. 176 (4): 806–834. doi:10.1111/zoj.12356. ISSN 0024-4082. https://doi.org/10.1111%2Fzoj.12356 ↩